Ganikobes: Artinskian, Namibia
collected by Brentano-Bernarda
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
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Mesosauridae
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Mesosaurus sp.
Gervais 1865
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1 individual | |||||||||
| no repository data given | ||||||||||
| see common names | ||||||||||
Geography
| Country: | Namibia | State/province: | Karas |
| Coordinates: | 25.8° South, 18.0° East (view map) | ||
| Paleocoordinates: | 56.0° South, 35.8° West | ||
| Basis of coordinate: | based on nearby landmark | ||
| Geographic resolution: | hand sample |
Time
| Period: | Permian | Epoch: | Cisuralian |
| Stage: | Artinskian | 10 m.y. bin: | Permian 2 |
| Key time interval: | Artinskian | ||
| Age range of interval: | 290.10000 - 283.50000 m.y. ago |
Stratigraphy
| Geological group: | Ecca | Formation: | ? Whitehill | ||
| Stratigraphic resolution: | group of beds | ||||
| Stratigraphy comments: "Offenbar handelt es sich um den wie verfestigter Bänderton aussehenden dickbankigen hellen Schiefer, den Range (1912. p. 30 und 52) als besonders bei Keetmanshoop verbreitet und als Hangendstes seiner 'Eurydesma-Stufe' angibt und mit dieser zusammen der Ecca-Stufe zurechnet. [Apparently, this is the bright banked shale looking like banded claystone which Range (1912 p. 30 and 52) mentiones as to be particularly occuring at Keetmanshoop, and as the uppermost hanging-wall rock of his 'Eurydesma-Stage', and which he, along with the latter, assigns to the Ecca beds.]" (Stromer, 1914).
The term "Eurydesma-Stufe" probably refers to interglacial beds of the upper part of the Dwyka Group of modern nomenclature, in which the bivalve Eurydesma is common (see, e.g. Césari, 2007, Gondwana Res. 11(4)). Thus, the beds in question can be no older than Upper Dwyka age. Oelofsen & Araujo (1987, S. Afr. J. Sci. 83) say that the occurrence of mesosaurs in southern Africa is exclusively restricted to the Whitehill Formation ("the White Band") of the Ecca Group. Thus, the present collection is tentatively assigned to the Whitehill Fm. Radiometric ages of the Collinson Fm. (overlying the Whitehill Fm.) vary between 270 and 275 Ma (Turner, 1999, J. Afr. Earth Sci. 28(1); Fildani et al., 2007 J. Sedim. Res. 77), and radiometric ages of the basal beds of the Prince Albert Fm. (underlying the Whitehill Fm.) vary between 293 and 285 Ma (Bangert et al., 1999, J. Afr. Earth Sci. 29(1)), implying an Artinskian age for the Whitehill Fm. (see time scales of Gradstein et al. (2004) and Ogg et al. (2008)). Radiometric dating within the Whitehill Fm. of the Khabus area (280.5 Ma; Werner, 2006, PhD thesis, http://www.opus-bayern.de/uni-wuerzburg/volltexte/2007/2175/pdf/00-Complete_thesis-STD.pdf) corroborates an assigment to the Artinskian. | |||||
Lithology and environment
| Primary lithology: | planar lamination,gray,green "shale" | ||
| Includes fossils? | Y | ||
| Lithology description: "Es ist ein sehr fester Tonschiefer von grünlichgrauer bis hellgrauer farbe und so feingeschichtet, daß er im Querbruche wie gebändert aussieht. Er spaltet nach Schichtflächen in 1-5 cm dicke Platten und ist in eckige, selten über 1 dm große Stücke zerbrochen, deren alte Bruch- und Schichtflächen durch Eisen[oxid]überzug braun gefärbt sind. [It is a very solid shale of greenish gray to light gray colour and it is finely bedded in a way that it looks banded on transverse crack surfaces. It cleaves along bedding planes into 1-5 cm thick slabs and is broken into angular pieces which are rarely larger than 1 dm, and whose older crack surfaces are brown due to a cover of iron [oxide]]." (Stromer, 1914). | |||
| Environment: | marine indet. | Tectonic setting: | cratonic basin |
| Geology comments: There is no consensus about the true nature (lacustrine/brackish/fully marine) of the water body in which the mesosaurs lived. The environment is tentatively chosen to have been marine. | |||
Taphonomy
| Modes of preservation: | mold/impression |
| Size of fossils: | macrofossils |
| Articulated whole bodies: | none |
| Temporal resolution: | time-averaged |
| Spatial resolution: | autochthonous |
Collection methods and comments
| Collection methods: | surface (float),acetic |
| Reason for describing collection: | taxonomic analysis |
| Collectors: | Brentano-Bernarda |
| Collection method comments: The fossil should be reposited in one of the collections in Munich. | |
| Taxonomic list comments:"Da ich also ganze Skelette und Schädel nicht habe, kann ich eine genaue Bestimmung kaum ausführen. Jedenfalls ist kein Anhaltspunkt gegeben, daß es sich um andere Reste als von Mesosauridae handelt. Weil von deren zwei Genera nur Mesosaurus in Südafrika vorkommt, überdies nichts für die große Rumpfwirbelzahl von Stereosternum spricht, wird es sich wohl nur um Angehörige jener Gattung handeln. [Since I do not have complete skeletons or skulls, I can hardly make a precise determination. There is no evidence anyways that there are remains of other than Mesosauridae. Since of the two genera of the latter only Mesosaurus is present in southern Africa, and, furthermore, nothing points towards the high number of trunk vertebrae of Stereosternum, the remains only may represent the former genus.]" (Stromer, 1914).
The collection includes one of the two specimens which were not collected on the hill of the Hauptmannshaus at Kabus. | |
Metadata
| Also known as: | Ganigobes; Kalahari Basin; Karoo | ||
| Database number: | 90780 | ||
| Authorizer: | J. Mueller | Enterer: | T. Liebrecht |
| Modifier: | T. Liebrecht | Research group: | vertebrate |
| Created: | 2009-08-17 05:33:14 | Last modified: | 2009-08-26 06:56:06 |
| Access level: | the public | Released: | 2009-08-17 05:33:14 |
| Creative Commons license: | CC BY | ||
Reference information
Primary reference:
| 30516. | E. Stromer. 1914. Die ersten fossilen Reptilreste aus Deutsch-Südwestafrika und ihre geologische Bedeutung. Centralblatt für Mineralogie, Geologie und Paläontologie 1914:530-541 [J. Mueller/T. Liebrecht/T. Liebrecht] |